Electrickery

This time last year I was still hanging on the buoy. It was mild weather and I didn't need a heater.
This year the winter has come a bit earlier and I've swung over to the visitor pontoon to allow me to plug into the shore power so I can put a heater on. Yes, (sigh) I have not fitted a diesel heater yet.
So I show the dog the rabbit, and plug the cable in. But. The moment I turn the shore power on in the boat it trips out the whole pontoon power box.
Bugger
It's an old patched cable. It must be that.
Nope.still tripping out the box. new cable is lovely though.

It's a dodgy plug socket. It was getting warm last winter. I'll just replace that.

Nope. Not that either.
Still tripping the box out.
Fault finding will be turned up a notch in daylight.
Could be new battery charger time...
In the mean time I'm running the cable through a hatch and directly to my heater.
The wind generator is keeping the batteries topped up.
Except there's no wind...